Carbazole compounds

ABSTRACT

A composition comprising an aromatic copolyestercarbonate having flexural modulus, flexural yield and secondary transition temperature improvement over a corresponding aromatic polycarbonate effective amount of ester units of the structure ##STR1## or mixtures of the above two structures wherein R 1  and R 2  are the same or different and are alkyl of one to six carbon atoms, inclusive, cycloalkyl of four to seven carbon atoms, inclusive, phenyl, one to three alkyl substituted phenyl each alkyl having one to three carbon atoms, inclusive, and R 1  and R 2  taken together with the nitrogen to which they are attached form a ring of four to six carbon atoms, inclusive, or carbazole.

This is a division of copending application Ser. No. 657,897, filed Oct.5, 1984, now U.S. Pat. No. 4,622,379.

BACKGROUND OF THE INVENTION

Aromatic polycarbonates having relatively high modulus, flexuralstrength and secondary transition temperatures are well known in theart. One of the methods known of raising the secondary transitiontemperature of polycarbonates while substantially maintaining asignificant number of the other properties of polycarbonate is toincorporate a significant number of ester bonds, particularly aromaticester bonds. In this manner, a copolyestercarbonate is produced, seeGoldberg U.S. Pat. No. 3,169,121 incorporated by reference.Copolyestercarbonate with relatively high secondary transitiontemperatures are known, see Miller U.S. Pat. No. 4,465,820 and U.S. Pat.No. 4,464,512, for example. However, none of these disclosures appear tomention the effect of having a substituent on the aromatic ester ringother than the usual "hydrocarbyl", "chloro", "alkyl", etc. groups.

A substantially sized, double heteroatom group has now been placed intothe backbone of a copolyestercarbonate, the substantially sized doubleheteroatom group functioning as a side group instead of joining onerepeating unit to another. This group provides a high flexural modulusas well as a high secondary transition temperature with fewer esterunits than necessary in prior copolyestercarbonates.

SUMMARY OF THE INVENTION

In accordance with the invention, there is a composition comprising anaromatic copolyestercarbonate having flexural modulus, flexural yieldand secondary transition temperature improvement over a correspondingaromatic polycarbonate effective amount of ester units of the structure##STR2## or mixtures of the above two structures wherein R₁ and R₂ arethe same or different and are alkyl of one to six carbon atoms,inclusive, cycloalkyl of four to seven carbon atoms, inclusive, phenyl,one to three alkyl substituted phenyl each alkyl having one to threecarbon atoms, inclusive, and R₁ and R₂ taken together with the nitrogento which they are attached form a ring of four to six carbon atoms,inclusive, or carbazole.

DETAILED DESCRIPTION OF THE INVENTION

The copolyestercarbonates of this invention are prepared by reacting adihydric phenol with a carbonate precursor and the aromatic esterprecursor. The dihydric phenols employed in the preparation of thecopolyestercarbonate are those typically used and are illustrativelyexemplified below

2,2-bis(4-hydroxyphenyl)propane;

bis(4-hydroxyphenyl)methane;

2,2-bis(4-hydroxy-3-methylphenyl)propane;

4,4-bis(4-hydroxyphenyl)heptane;

2,2-(3,5,3'-5'-tetrachloro-4,4'-dihydroxyphenyl)propane;

2,2-(3,5,3',5'-tetrabromo-4,4'-dihydroxydiphenyl)propane;

(3,3'-dichloro-4,4'-dihydroxyphenyl)methane.

Other dihydric phenols which are also suitable for use in thepreparation of the above polycarbonates are disclosed in U.S. Pat. Nos.2,999,835; 3,028,365; 3,334,154 and 4,131,575.

The carbonate precursors are the usual ones, phosgene preferred, as setout in U.S. Pat. Nos. 4,018,750 and 4,123,436, interfacial process orthose used in transesterification processes as in U.S. Pat. No.3,153,008.

The aromatic precursors of the amide containing unit of the polymer areset forth below: ##STR3## or mixtures of both of these structures.

These amide substituted iso and terephthalic acids of FIG. 3 areprepared by reacting 1,2,4-benzene tricarboxylic anhydride, also knownas trimellitic anhydride ##STR4## at an elevated temperature followed byaqueous acid work up. The temperature used for the reaction can varyfrom about 110° to 175° C. Reaction time is not critical and can varyfrom about 8 to 16 hours. The monomers represented in FIG. 3, R₁ R₂ aspreviously defined, are novel compounds and are a further aspect of thisinvention. As used in R₁ and R₂ the phrase "alkyl of one to six carbonatoms, inclusive", includes normal and branched groups including interalia methyl, ethyl, isopropyl, n-butyl, tert.butyl, neopentyl andisohexyl. Branched alkyl groups are preferred.

The preparation of the copolyestercarbonate of this invention canproceed by the usual known procedure. However, wherein certain of themonomers of FIG. 3 are slow in incorporating into the chain as evidencedby low intrinsic viscosity values or a low maximum level ofincorporation, slight modification of the usual reaction procedure arenecessary.

Typical reaction procedures that are employed are the mixing together ofthe dihydric phenol, endcapping agent (usually phenol orp.tert.butylphenol) and then phosgenating the reaction vessel for aspecified period of time, usually providing 10 to 20% more phosgene thantheoretically necessary for total phosgenation in the usual type ofinterfacial polymerization. This polymerization uses aqueous alkaline pHand methylene chloride in the reaction procedure. As the mole percentamide monomer incorporation goes upward to the 50 to 60 mole percent,the presence of a chain stopper is found to be essentially unnecessarysince the reaction rate of incorporation of the amide appears to becontrolled by the reaction conditions. It has been found that betterresin can generally be obtained by dividing the quantity of dihydricphenol into several portions. The initial portion being present with allthe amide monomer and the remainder of the dihydric phenol added partway through the phosgenation. Generally this somewhat modifiedinterfacial polymerization procedure will provide better resin than thestandard procedure as measured by physical properties and purity.Although not understood completely it is believed that the resinformation reactions are essentially a competition between two reactionsequences, one leading to an ester unit and one to a carbonate unit.

The preparation of the copolyestercarbonate has been examplified aloneas a reaction between a dihydric phenol, a carbonate precursor, and anamide containing aryl diester precursor. Obviously more than onedihydric phenol can be present in the molecule, the preferred one beingbisphenol-A. It is also appropriate to have another aryl diesterprecursor present such as ordinary isophthalic acid, terephthalic acid,acid chlorides of either acid or mixtures of both iso and terephthalicacid and their acid chlorides.

The amount of amide monomer, i.e. FIG. 3, in the copolyestercarbonatewill generally vary from about 5 to about 60 mole percent based on themoles of dihydric phenol present. Preferred amounts are from about 10 to50 mole percent.

Below are examples of the invention. These examples are intended toexemplify the broad nature of the invention rather than narrow it.

PREPARATION OF THE AMIDE SUBSTITUTED ACIDS OF FIG. 3

Preparation A

Mono diphenyl amide of 1,2,4-benzene tricarboxylic acid (FIG. 3, R₁ andR₂ are phenyl)

192 g (1.0 mole) of 1,2,4-benzenetricarboxylic anhydride (Aldrich) and169 g (1.0 mole) diphenyl amine (Eastman Reagent) were mixed in a 1000ml 3-neck flask fitted with a mechanical stirrer and with a condensercapped with a drying tube. The flask was warmed in a 90° C. oil bathuntil the diphenyl amine was melted. To the flask was then added 250 g(2.5 mole, dried over 4 A⁰ molecular sieves) triethyl amine. Thetemperature was raised to 110° C. and then to 120° C. After 3 hoursvigorous stirring, the reaction mixture had become a thick brown melt.After 8 hours reaction time, the heat was turned down to about 80° C.for 16 hours (overnight) then turned back to 120° C. for one hour. An irspectrum of the reaction mixture indicated negligible residual anhydrideand strong amide and carboxylate salt groups absorbances. Excesstriethyl amine that had collected on top of the reaction mixture waspoured off. Then 375 ml distilled water was added to the hot melt toyield a clear brown solution. The solution was filtered into a 4000 mlErlenmeyer flask, diluted with 1000 ml acetone, acidified to pH<1 withconc. aq. HCl (about 150 ml). The solution was split into two equalportions and each portion diluted to 4000 ml with water to yield agranular precipitate. The precipitate was collected by vacuum filtrationand any large lumps broken up, then washed 2× with 2000 ml water (pH ofsecond wash was 4 to 5). After drying in a 45° C. vacuum oven, a paleyellow powder was obtained. ir 1710 cm⁻¹, 1650 cm⁻¹ (shoulder), 1595cm⁻¹. This powder is suitable for use directly in resin preparation.

The following amides were prepared in essentially the same manner as thediphenyl amide of preparation A.

Preparation B

Carbazole derived amide (FIG. 3, R₁ and R₂ taken together with nitrogento which they are attached form a carbazole) ##STR5##

The initial reaction product (the bis triethylammonium salt of FIG. 3;N,R₁ and R₂ as shown in FIG. 6) appeared to partially crystallize as thereaction proceeded. A nearly solid reaction mixture resulted which couldnot be stirred and was not soluble in water. It was acidified as anaqueous slurry instead of in solution. Subsequent workup was the same asfor A: ir 1700 cm⁻¹, 1650 cm⁻¹ (shoulder).

Preparation C

Dicyclohexyl amide (FIG. 3, R₁ and R₂ are each cyclohexyl)

The reaction was carried out at the usual temperature (110° to 120° C.)for three hours, then the temperature was increased to 145° C. for fourhours. The higher temperature was necessary to allow stirring of thereaction mixture which became an extremely viscous, dark red melt as thereaction proceeded. Also, after 5 hours reaction time, more dicyclohexylamine (9 g, 0.05 mole) was added. Workup was the same as for A: ir 1705cm⁻¹, 1610 cm⁻¹.

Preparation D

Diisopropyl amide (FIG. 3, R₁ and R₂ are isopropyl)

The flask containing only the 1,2,4-benzene tricarboxylic anhydride wasfirst heated to 175° C. to melt the anhydride. A mixture of 111 g (1.1mole) diisopropylamine and 250 g (2.5 mole) triethylamine was then addedin portions over about 4 hours from an addition funnel at such a ratethat refluxing was vigorous but controlled. Reaction temperature wasgradually lowered to 150° C. during addition of the amines. Thismodified procedure was necessary because when the reaction was run inthe usual manner (all the amines added at the start) the refluxingamines prevented the reaction mixture from reaching a temperature atwhich reaction would proceed at a practical rate. Subsequent reactionand workup were the same as for A: ir 1725 cm⁻¹, 1610 cm⁻¹.

EXAMPLE 1 Copolyestercarbonate with 60 mole percent amide

A 2000 ml 4-neck flask was fitted with a mechanical stirrer, a phosgeneinlet tube, a pH probe and a Claissen adaptor to which were connected acaustic inlet tube and a dry ice condenser. In the flask were mixed 85.5g bisphenol-A (0.375 mole), 81 g of the diphenyl amide, preparation Aabove (0.225 mole), 1.05 ml triethylamine, 420 ml water and 350 mlmethylene chloride. With slow stirring and pH controlled at 7 to 8,phosgene was introduced into the flask at 0.3 g/min. for 180 minutes.The stirrer speed was then increased and the pH was gradually raisedfrom 9 to 10 at 190 minutes. Then 125 ml methylene chloride was addedand the phosgene rate increased to 1.0 g/min. At 213 minutes totalphosgenation time, the reaction was terminated. The resin layer wasseparated from the brine layer, diluted with 250 ml methylene chloride,then washed twice with 0.01N HCl and once with water and precipitated in3× volume of methanol in a Waring blender. The resin had an IV of 0.684and Tg of 195.1° C. and ir 1770 cm⁻¹, 1740 cm⁻¹, 1665 cm⁻¹ and 1595cm⁻¹.

This basic procedure of Example 1 was used to prepare the followingresins. Modifications in procedure were made several times in the twovariables, phosgenation rate and methylene chloride level, when itappeared necessary in order to produce resin of satisfactory intrinsicviscosity. Generally, the slower the phosgenation rate or the lower themethylene chloride level, the better the reaction proceeded. Conditionsare shown in the Table below. The quantity of methylene chloride addedat the end of the reaction was variable, depending on the amount in theinitial formulation and the resin intrinsic viscosity. Generally, onlyenough was added to allow stirring of the reaction mixture.

                                      TABLE I                                     __________________________________________________________________________    REACTION CONDITIONS FOR PREPARATION OF THE AMIDE                              SIDE GROUP RESINS AND PROPERTIES OF THE RESINS                                                                  INITIAL                                                                             RESIN IV dl/g AT                                     BATCH SCALE                                                                            PHOSGENATION                                                                            CH.sub.2 Cl.sub.2                                                                   25° C. IN METHYL-              RESIN                                                                              FORMULATION                                                                             (MOLE)   RATE g/min.                                                                             ml    ENE CHLORIDE                                                                             TG °C.              __________________________________________________________________________    1    50 mole % A*                                                                            0.25     0.5       350   0.506      191.3                           no end-cap                                                               2    50 mole % B                                                                             0.25     0.5       350   1.62.sup.1 188.9                           no end-cap                                                               3    60 mole % A                                                                             0.375    0.3       525   0.497      190.9                           no end-cap                                                               4    60 mole % A                                                                             0.375    0.3       350   0.684      195.1                           no end-cap                                                               5    50 mole % C                                                                             0.375    0.3       350   0.456      199.6                           0.5 mole %                                                                     .sub.-t-butyl phenol                                                    6    60 mole % C                                                                             0.375    0.3       300   0.731      205.2                           no end-cap                                                               7    50 mole % D                                                                             0.375    0.3       300   0.622      189.0                           2.0 mole %                                                                     .sub.-t-butyl phenol                                                    8    60 mole % D                                                                             0.375    0.3       300   0.425      190.2                           no end-cap                                                               __________________________________________________________________________     .sup.1 Reduced viscosity at 0.4 g resin/100 ml CH.sub.2 CL.sub.2 at           25° C.                                                                 *Each of the letters refer to the same amide monomer prepared in the          Preparation section                                                      

EXAMPLE 2

The following resins were made with preparation A, diphenylamide, as theamide.

A. 10 mole % amide copolyestercarbonate

The formulation of the batch was as follows:

8.4 l water

6.0 l methylene chloride

21 ml triethylamine

3.4 g sodium gluconate

1710 g (7.5 mole) bisphenol-A

28 g (0.187 mole, 2.5 mole %) p-tert.butyl phenol

271 g (0.75 mole, 10 mole percent) amide monomer

The batch was phosgenated at 6 g/min. for 80 minutes at pH 6 to 8, thenat 6 g/min. for 80 minutes at pH 9 to 10 (1080 g total, 10.9 moles). Thebrine layer was then checked for free BPA. The batch was then dilutedwith 7 l methylene chloride, the brine layer separated by centrifuge,and the resin layer washed with acid (30 ml conc. HCl in 4 l water) andtwice with water (4 l). The resin was steam precipitated and dried on afluid bed dryer to about 240° F.

B. 10 mole % amide copolyestercarbonate prepared by modification methodutilizing splitting of dihydric phenol into two batches

The procedure of A above was followed except that 910 g (4.0 moles) ofbisphenol-A was added at the start and 800 g (3.5 mole) of bisphenol-Awas added at the end of the low pH phosgenation. Phosgenation was at 6g/min. at pH 6 to 8 for 50 minutes, then at 24 g/minute at pH 9 to 10for 25 minutes (1100 g. total, 11.1 moles).

C. 20 mole % amide copolyestercarbonate. Formulation was as follows:

8.4 l water

6.0 l methylene chloride

21 ml triethylamine

3.4 g sodium gluconate

1710 g (7.5 mole) bisphenol-A

28 g (0.187 mole, 2.5 mole %) p-tert-butyl phenol

542 g (1.5 mole, 20 mole %) amide co-monomer

The batch was phosgenated at 6 g/min. for 80 minutes at pH 6 to 8, thenat 6 g/min. for 80 minutes at pH 9 to 10 (1080 g total, 10.9 moles). Thebrine layer was then checked for free BPA (50 ppm). The batch was thendiluted with 7 l methylene chloride, the brine layer separated bycentrifuge, and the resin layer washed with acid (30 ml conc. HCl in 4 lwater) and twice with water (4 l). The resin was steam precipitated anddried on a fluid bed dryer to about 240° F.

EXAMPLE 3

The resins of Example 2 were extruded at 500° F. with 0.03 parts each ofa phosphite and an epoxy stabilizer and molded at 600° F. into testingsamples of dimensions 2.5 by 0.25 by 0.5 inches. The Tg, Flexural Yield,and Flexural Modulus were measured. The I.V. is measured in methylenechloride at 25° C.

    ______________________________________                                                  FLEXURAL   FLEXURAL                                                           YIELD      MODULUS                                                  EXAMPLE   psi        psi         I.V. Tg °C.                           ______________________________________                                        Bisphenol-A                                                                             14,300     342,000     0.49 150° C.                          Polycarbonate                                                                 (Control)                                                                     2A        15,500     370,000     0.566                                                                              160.0                                                                          (163.6)*                               2B        15,000     376,000     0.542                                                                              160.2                                                                          (162.8)*                               2C        16,400     390,000     0.573                                                                              165.0                                                                          (170.8)*                               ______________________________________                                         *Tg measured after sample redissolved in methylene chloride and then          solvent precipitated in methanol, following precipitation procedure of        Example 1.                                                               

What is claimed is:
 1. A compound of the formula ##STR6## wherein R₁ andR₂ taken together with the nitrogen to which they are attached formcarbazole.